What is a dieline? The complete guide for packaging

Every printed box starts as a flat drawing. That drawing, the dieline, tells the factory exactly where to cut, crease, glue and print. Get it right and the box folds perfectly with artwork lined up on every panel. Get it wrong and you find text running across a fold, a logo upside down on the lid, or a box that does not fit the product. This guide explains what a dieline is, the terms you will hear, how dielines are made and how to set up artwork on one.

What a dieline is

A dieline is a flat, two-dimensional technical drawing of a package, such as a box, sleeve, label or pouch, that shows its exact shape when unfolded. It is called a dieline because it is used to make the cutting die: a tool, usually steel rules set into a board, that cuts and creases the printed sheet.

The dieline is the template for both structure and artwork. The structural designer uses it to define the shape and folds; the graphic designer places artwork on it so everything lines up when the box is assembled.

The lines on a dieline

Dielines use different line styles and colours to mean different things. Conventions vary between factories, so always check the legend on your manufacturer's file, but these are the most common:

• Cut lines: usually solid lines, marking where the board will be cut through.
• Crease or fold lines: usually dashed lines, marking where the board will be scored so it folds cleanly.
• Perforation lines: dotted or dash-dot lines for tear strips or easy-open features.
• Bleed line: an outer line, usually 3 mm beyond the cut line, showing how far artwork should extend.
• Safe area or safety line: an inner line, usually 3 mm or more inside the cut and fold lines, showing where important text and logos should stay.
• Glue areas: shaded or marked areas where adhesive is applied; these should usually be left unprinted or have specific treatment.

Dielines are usually supplied as vector files, such as PDF, AI or DXF, with the dieline on a separate layer or as a spot colour so it does not print.

Key dieline terms

• Panel: each flat face of the box, such as front, back, sides, top and bottom.
• Flap: a part that folds in to close or strengthen the box.
• Tuck flap: a flap that tucks into the box to close it, as on a tuck end carton.
• Dust flap: a small flap that folds in under the tuck flap to keep dust out.
• Glue flap or manufacturer's joint: the strip where the box is glued to form a tube.
• Lock bottom or crash lock: bottom structures that lock into place for strength or fast assembly.
• Grain direction: the direction of fibres in the board, which affects folding and strength.
• Inside and outside dimensions: the internal size the product fits into, and the external size of the finished box.

How a dieline is made

1. Measure the product

Everything starts with accurate product dimensions: length, width and height, plus any irregular shapes, caps or handles. Our guide on how to measure box size explains how to do this properly.

2. Choose the box style

The box style, such as tuck end, mailer, rigid lid and base or drawer, determines the basic structure. Standard styles have well-established dieline patterns.

3. Account for the material

Board thickness changes everything. A 400 gsm folding carton, an E-flute mailer and a 2 mm rigid greyboard box all need different allowances at folds and joints. That is why a dieline made for one material will not work for another, even at the same internal size.

4. Draw the structure

A structural designer draws the dieline in CAD software, adding allowances for board thickness, fold tolerances and how the box will be made: by machine, by hand, or a mix.

5. Check and test

The dieline is checked against the product's dimensions and shown as a 3D mockup to confirm fit, closing and appearance. Adjustments are made before artwork is finalised.

Rigid box dielines are different

Rigid boxes, such as magnetic closure, lid and base and drawer boxes, are built differently from folding cartons. The structure is made from thick greyboard, then wrapped in printed paper. That means there are usually two sets of drawings:

• the greyboard structure, which defines the box's shape and size
• the wrap dieline, which is the printed paper that wraps around the board, including turn-ins that fold over the edges and inside

Wrap dielines need generous allowances for turn-ins, and artwork must account for the paper wrapping around corners. Placement of foils and embossing must avoid corners and edges where the wrap folds.

Setting up artwork on a dieline

Work in the right file

Use the dieline file from your manufacturer, at 100% scale. Keep the dieline on its own locked layer, set to a spot colour or overprint, and clearly marked as non-printing.

Extend backgrounds to the bleed

Any colour or image that touches a cut edge should extend to the bleed line. If cutting shifts slightly, the bleed prevents white edges.

Keep important content in the safe area

Logos, text, barcodes and key graphics should stay inside the safe area, away from cut and fold lines. A barcode across a fold will not scan; text across a crease cracks and becomes hard to read.

Check orientation

On a flat dieline, some panels will appear upside down or sideways relative to how they will be seen on the finished box. Lids, tuck flaps and bottom panels are common mistakes. Fold a printed paper mockup to check.

Plan the glue areas

Leave glue flaps unprinted or as specified by your manufacturer. Ink and coatings can stop adhesive from bonding.

Separate finish layers

Foil, spot UV, embossing and debossing each need their own layer or spot colour, aligned exactly with the artwork. Label them clearly.

Use the right colour mode

Set up print artwork in CMYK or the agreed spot colours, not RGB. Our guide to Pantone vs CMYK explains when to use each.

Check text sizes and legibility

Small text on board can fill in or break up, especially on uncoated or corrugated materials. Check minimum sizes with your printer.

Common dieline mistakes

• Using a dieline for the wrong material or a free template from the internet.
• Artwork not extended to bleed.
• Text or logos across folds or too close to edges.
• Panels upside down after folding.
• Printing on glue areas.
• Finish layers misaligned with the artwork.
• Changing the product size after the dieline is made without updating it.
• Ignoring grain direction on large boxes, causing poor folds.

Dielines for labels and pouches

Dielines are not just for boxes. Labels have dielines showing the cut shape, bleed and safe area, and sometimes the curve or seam position on the container. Pouches have dielines showing the front, back and gusset, seal areas, zip and tear notch positions. The same principles apply: bleed, safe areas, orientation and finish layers.

How we help

We design packaging and make rigid and printed boxes in our own factory, so we build dielines for the board, machines and finishes that will actually make your box. We check structures on a 3D mockup before artwork is final, set up artwork on the real dieline, and check every panel before production.

See our structural and dieline design and box packaging design services, or get a free quote with your product size.

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Questions

What is a dieline in packaging?

A flat technical drawing of a box or label that shows where it will be cut, folded, glued and printed.

Who makes the dieline?

Usually the packaging manufacturer or a structural designer, based on the product's dimensions and the chosen box style.

What is bleed on a dieline?

Extra artwork that extends beyond the cut line, usually 3 mm, so no white edge shows if cutting shifts slightly.

Can I use a free dieline template?

For ideas, yes. For production, use the dieline from your manufacturer, because board thickness and machine tolerances change the measurements.

How accurate does a dieline need to be?

Very. Small errors of a millimetre or two can stop a box closing properly or leave a gap around the product, so production dielines are drawn to the board thickness and machine tolerances.

What file format should a dieline be?

Usually a vector file such as PDF, AI or DXF, with the dieline on its own layer or spot colour so it does not print.